1. Field of Invention
Animal litter prepared for household pets and laboratory animals has been marketed for several years and has found wide acceptance. The size of the available market is considerable when it is considered that the potential market for cat litter alone in the United States is about 1.3 pounds of litter per capita of human population annually.
As is to be appreciated, more leeway can exist in the type of material acceptable for laboratory animals and household pets when the litter is of the non-contact type, whereas strict controls must be maintained with direct contact litter. With non-contact litter, absorbent properties, odor and dust control, price and ease of litter disposal are of prime importance. In addition to these factors, other things such as lack of nutritive value or attractiveness as feed, and absence of skin irritant properties are important in contact litters. Further, it is important to consider the cost of raw materials, basic absorbent properties of the litter in relation to weight, resource allocation such as whether or not the raw materials have to be produced, as in the case of alfalfa, or mined and treated as in the case of clay.
2. Prior Art
Generally known litter compositions are either compositions containing large amounts of clay or natural grass compositions containing a natural grass such as alfalfa. Alfalfa containing compositions contain compressed alfalfa for absorbing liquid. The alfalfa contains chlorophyll which also acts as an odor suppressant. The patent ot Bickoff et al. U.S. Pat. No. 3,747,564 shows one such composition. The McFadden U.S. Pat. No. 3,286,691 discloses an alfalfa containing composition which may also contain a clay such as bentonite. One particular method for preparing a clay-alfalfa litter composition is disclosed in U.S. Pat. No. 3,789,979 of Brewer. While the alfalfa or grass contains chlorophyll which acts as an odor suppressant, the alfalfa has a strong odor itself, particularly when wet, and may smell like "silage" which renders its use unacceptable for many applications, particularly in confined areas, such as apartments and the like.
The use of many conventional litter materials is somewhat objectionable in that they fail to sufficiently suppress odors caused by the liquid waste materials or they possess distinct odors of their own. As noted, one method suggested by the prior art to reduce this problem is by the addition of an odor controlling agent such as chlorophyll.
U.S. Pat. No. 3,735,734 describes an odor suppressing litter material which contains a combination of a synthetic chlorophyll containing compound and an odor inhibiting additive such as sodium dihydrogen phosphate. In addition, this patent describes the use of a large number of substances commonly used as litter materials for animals. Such substances include peanut hulls. However, as further noted in the patent, it has been found that peanut hulls are too light and are easily kicked out of an animal commode or tracked about the premises by the animal thus rendering them unsatisfactory. The Peanut Journal and Nut World Volume XIV, No. 4., February 1975, pages 15 and 16 also refers to the use of peanut hulls as a poultry litter and proposed animal litter.